This invention relates to vacuum treating apparatus, and particularly, but not limited to, high production, high quality sputtering apparatus for depositing materials on substrates.
Various vacuum treating apparatus, including various conventional sputtering apparatus, require a vacuum pump down each time a batch of workpieces is loaded into the apparatus. The pump down time can be quite extensive, often being an appreciable portion of the entire processing sequence, and it is thus desirable to reduce it. This is one object of this invention.
Obtaining reproducible results from workpiece to workpiece requires that all the workpieces be treated or operated on in substantially identical fashion. One problem heretofore existing in certain types of vacuum treating apparatus in which different workpieces of a batch of workpieces are successively operated on over a period of time is that of providing uniform treating conditions throughout the treating period, particularly at the beginning and end of the period.
A further object of this invention is to provide uniform and reproducible treatment of different workpieces successively operated on in a vacuum treating process.